Configuring DNAT on Juniper SRX300

I have a web server (10.9.21.17) behind my Juniper SRX firewall. I want to make it available to the Internet. I have one static public ip address (1.1.1.116) and it is bound to the interface facing the Internet

I have two web servers (10.9.21.17 and 10.9.21.90) behind my Juniper SRX firewall. I want to make both available to the Internet. I have one public ip address (1.1.1.116) bound to the interface facing the Internet to be used with the first web server (10.9.21.17) and a second ip address (1.1.1.73) that will be used with the second web server (10.9.21.90)